Antigen-induced cytokine production in lymphocytes of Eimeria bovis primary and challenge infected calves.
Cellular immune responses against Eimeria bovis are highly specific and a key factor for the development of protection against challenge infections. In this study we investigate the cellular immune responses of E. bovis primary and challenge infected calves stimulated in vitro by E. bovis merozoite I-antigen. Primary infection was accompanied by an increase of IFN-gamma and IL-2 gene transcription in whole blood samples, peaking during prepatency (8-12 days p.i.) and declining thereafter, whereas IL-4 gene transcription was induced predominantly in patency. IL-10 mRNA was not influenced by E. bovis infection. Both CD4+ and CD8+ T cells were identified as source of IFN-gamma gene transcripts, whilst IL-2 and IL-4 gene transcription was enhanced mainly in CD4+ T cells. Increased levels of IFN-gamma transcripts and protein were also found in lymphocytes isolated from ileocaecal lymph node biopsy 8 days p.i., and in cell culture supernatants obtained from antigen-stimulated peripheral blood mononuclear cells (PBMC) at days 8 and 12 p.i., respectively. Challenge infections of calves influenced neither IFN-gamma nor IL-2 gene transcription in peripheral blood or in lymph node-derived lymphocytes. In contrast, IL-4 gene transcription was increased in lymphocytes isolated from draining lymph nodes. Besides antigen-specific reactions we also found an infection-triggered induction of the non-specific activation state of PBMC in the course of primary infection as measured by the intracellular IFN-gamma and IL-4 content of phorbol-12-myristate-13-acetate/ionomycin-stimulated PBMC. This may represent a new mechanism of immune cells of E. bovis-infected calves contributing to ongoing immune reactions.
Taubert
Anja
A
Institute of Parasitology, Justus Liebig University Giessen, Rudolf-Buchheim-Str. 2, D-35392 Giessen, Germany. Anja.Taubert@vetmed.uni-giessen.de
Hermosilla
Carlos
C
Sühwold
Anke
A
Zahner
Horst
H
D000704:Analysis of Variance; D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology* / Q000469:parasitology*; D003048:Coccidiosis / Q000276:immunology / Q000662:veterinary*; D016207:Cytokines / Q000276:immunology*; D017931:DNA Primers / Q000235:genetics; D004539:Eimeria / Q000276:immunology*; D005786:Gene Expression Regulation / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary
D000953:Antigens, Protozoan; D016207:Cytokines; D017931:DNA Primers